Optical fiber is commonly made in a manufacturing process in which fiber is drawn from a glass preform into a thin strand of fiber many kilometers long. In most, if not all of these processes, this process begins with lowering a fiber preform into a furnace and heating it to a temperature sufficient to make the lower end of the preform sag into a gob. As the temperature of the lower end of the preform increases, this gob continues to narrow in diameter until it is sufficiently thin, and the viscosity of the glass is sufficiently low, to enable a strand of fiber to be continuously pulled from the preform.
The beginning of this process thus commonly involves threading the leading end of the fiber through the various apparatus employed in the fiber draw process, e.g., a fiber coating system for applying a protective coating onto the fiber, a fiber cooling system if one is employed, and various diameter measurement devices. The fiber is then attached to a device known as a tractor which continuously pulls the fiber through the draw apparatus, after which it is wound onto spools.
One way of accomplishing the initial task of threading the lead end of the fiber through the draw apparatus is to have the fiber manually thinned by a worker and then manually threaded down the draw tower and through the fiber cooling and coating systems, etc. During this process, the fiber often must be broken multiple times to maintain the proper diameter. In addition, the fiber often breaks by accident. In either case, the process of threading the fiber can become quite tedious and time consuming. In addition, stray fiber from this breakage often ends up in the cooling and/or coating systems, and can become a source of abrasions during the manufacturing process. If this occurs, it is often not detectable until after all of the fiber is drawn, in which case an entire spool of fiber may have to be scrapped. The difficulty with this process is magnified by the fact that these apparatus often occur on different floors of the manufacturing facility, and thus require more than one manual worker to thread the fiber through the apparatus. It is also magnified by the inconsistency from worker to worker in how the glass is thinned and the appropriate fiber diameter is determined prior to beginning the threading process. Adequately judging the proper fiber diameter can be crucial to the successful threading of the beginning of the draw process. Because of all the difficulties in manually threading the fiber by hand through the process, this process can sometimes take as long as 30 minutes or more to complete.
It would therefore be desirable to design an alternative method for feeding the leading edge of a fiber through the various apparatus of the draw process.